Process of making phthalic anhydride



Patented July 6, 1926.

UNITED STATES PATENT OFFICE.

mar-1r n. ones, or mamas oaovn rmw JERSEY, assmnoa To a I. no rom nnmopns a com-m, or wmnmo'ron, rlmwaaa, a oonrona'nou or DELA- WARE.

No Drawing.

This invention relates to the production of hthalic anhydridefrom'derivatives of nap thalene suc for example, as methyl na hthalenes.

t is well-known that naphthalene can be oxidized catalytically tophthalic anhydride by the action of vanadic oxide catalysts uponmixtures of naphthalene and air, or an oxygen-containing gas in thevapor phase. I ave now discovered that derivatives of naphthalene, forexample, methyl naphthalenes, can be oxidized in the same way tophthalic anhydride, thus makin it possible tojemplo all of the crudergra es of naphthalene or the production 'of phthalic an hydride by thevapor phase process.

One way of practicing my invention is set forth in the followingexample:'

Methyl naphthalene is vaporized into an air stream in such proportionsthat the oxygen of the air stream is present in about twice thetheoretical quantity required for the oxidation of the methylnaphthalene to phthalic anhydride. This gas stream is then passedthrough over, or in contact with an oxide of vanadium or of molybdenumat temperaturespreiera'bly about 400-C., but which may-'be varied from300 to 650 C. The ghthalic anhydride produced is condense from the gasstream in the usual 1118611181.

xy en-containin ases' can n eneral be used for the oxi da tion, but in practice it has been found most economical to use atmospheric air. Theroportion of air to hydrocarbon should be in such ratio that the oxygenpresent is about twice the theoretical quantity required to do the work.This uantit of air may be varied within wide limits rom 1 thetheoretical quantity re uired to 4 or 5 times the theoretical quantitrequired.

n regard to the catalyst, other catalysts than vanadi'c oxide may beused, although it is believed that vanadic oxide in the fused conditionor upon a carrier as described in my previous patent application, Ser.No. 379,545 filed May 7, 1920, is the best form of catalyst. Otheroxidation catalysts can be used; for example, oxides of mol-yb denum,and to a lesser degree of efliciency, oxides of chromium and titanium.

To illustrate the practical operation of my 'tion in a centrifuPBOCESBOF m0 PHTKAI-IC ANKYDBIDE.

E ulation 'fled October so, [920. Serial at. 420,603.

I shall describe in detail the preprocedurc: Crude naphthalene obtainedby the separation of the proper coal tar fractions on distillation isfreed from a considerable portion of the oils "by revolu- 1 machine. Tis crude is known commercially as whizze'd naphthalene and which ma varygreatly in purity, consists principa ly of pure naphthalenejto theextent of to 80%, and usually contains cohsiderable quantities (ifmethyl na'phthalenes and other ring compounds. This material is fed at auni orm rate into a vaporizer where it is converted into the gaseousphase and mixed with the desired quantity of air or otheroxygen-containing gas. From this vaporizer the gaseous mixture is passedinto intimate contact with the catalyst consisting of vanadic oxideeither upon a carrier or in articles of varying sizes made from the usedoxide. The tem erature of the cats l at is maintained at rom 350 to 500;O. he products of thereaction are passed into a condenser where thegases are cgoled and phthalic anhydride, benzoic acid, naphthaphthalicanh dride, benz'oic acid, naphthalized from t e gas phase; these solidsare then separated from the gas stream. I have found thatfractionalseparations of these substances can be made in a condenser, so that theproducts of the reaction'can be separatedin a' comparatively pure state.

The recesses above described may be varied in many ways withoutdeparting from my invention. Thus, oxygen may be substituted wholly orin part for air, or the air or oxygen may be mixed with a gas which isrelatively inert.. The gas mixtures may be brought in contact wit or'forced through the catalyst in many dlfl'erent ways, and it has beenfound advisableto carry on the reaction at a considerable pressure,varying from one to three atmospheres, that is, from 2 to 4 atmospheresabsolute pressure. The proportion of naphthalene and alkylnaphthalenevapors to the ox gexrcontaming gas mixture may be varier within wideprocess, erred naphthalene, whi'c limits.

I claim:-

1. The process of producing Ehthalic au hydride which comprises 8Ujecting an :ilkyl-naphthalene in a gaseous state and mixed with anoxygen-containing gas to the action of an oxidation catalyst at atemperature of from about 300 to 650 C.

2. The process of producing phthalic anhydride which compriscsjubIectingcrude naphthalene, containing an a kyl-naphthe- Zone, in a gaseous stateand mixed with an ox tan-containing gas to the action of an oxufationcatalyst at a temperature of from about 300 to 650 C.

3. The process of producing phthalic anhydride which comprisessubjecting crude naphthalene, containing a methyl-naphthalene in agaseous state and mixed with an 0 ex diition catalyst at a temperatureof from about 350 to 500 C.

4. The recess of producing phthalic anhydride w ich comprises bringing agaseous mixture containing oxygen and vapors of an alkyl-naphthaleneinto contact with an oxide of vanadium maintained at a temperature offrom about 300 to 650 C.

5. The recess of producing phthalic anhydride w rich comprises bringingn. gaseous mixture containing oxygen and vapors of crude naphthalenecontaining an ulkylnaphthalene into contact with an oxide of vanadiummaintained at a temperature of from about 300 to 650 C.

Theprocess of producing phthalic anhydride which comprises bringing agaseous mixture containing oxygen and vaigora of crude naphthalenecontaining an a yixy en-confmning gas to the action of an mixturecontaining naphthalene into contact with an oxide of vanadium maintainedat a temperature of from about .350 to 500? C. a

7. The process of producing phthalic anhydricle which comprises subecting a mixture of air and crude na hthalene vapors containing analkyl-naphtiialene to the action of vanadic oxide at a temperaturebetween 300 and 600 C.

producin phthalic anlCil comprises subjecting a mixture of crudenaphthalene vapors and air unpressure of from 2 to 4 atlilospheres tothe action of vanadie oxide at wtem eruture between 300 and 650 C.

S). he process of producing .phthalic anhydriilc which comprisesbringing a gaseous mixture containing oxygen and vs ors of crudenaphthalene containing an a] lnaphthalene under an absolute pressure offrom 2 to 4 atmospheres into contact with an oxidation catalyst at atemperature of from about 300 to 650 C.

10. The process of producing phthalic an hydride which comprisesbringing a. gaseous oxygen and vapors of crude naphthalene containing,an alkyluaphthnlene under an absolute pressure of from 2 to 4atmospheres into contact with an oxide of vanadium or molybdenum at atemperature of from about 300 to 650 C;

In testimony whereof I afiix my signature.

HARRY D. GIBBS.

mixed with an oxygen-containing gas to the action of an oxidationcatalyst at a temperature of from about 300 to 650 C.

2. The process of producing phthalic anhydride which comprisessubi'ecting crude naphthalene, containing an a kyl-naphthalene, in agaseous state and mixed with an ox gen-containing gas to the action ofan oxidation catalyst at a temperature of from about 300 to 650 C.

3. The process of producing phthalic anhydride which comprisessubjecting crude naphthalene, containing a methyl-naphthalene in agaseous state and mixed with an oxygen-containing gas to the action ofan oxidation catalyst at a temperature of from about 350 to 500 C.

4. The process of producing phthalic anhydride which comprises bringinga gaseous mixture containing oxygen and vapors of an alkyl-naphthaleneinto contact with an oxide of vanadium maintained at a temperature offrom about 300 to 050 C.

5. The process of producing phthalic anhydride which comprises bringinga gaseous mixture containing oxygen and vapors of crude naphthalenecontaining an alkylnaphthalene'into contact with an oxide of vanadiummaintained at a temperature of from about 300 to 650 C.

6. Theprocess of producing phthalic anhydride which comprises bringing agaseous mixture containing oxygen and vapors of crude naphthalenecontaining an alkylnaphthalene into contact with an oxide of vanadiummaintained at a temperature of from about 350 to 500 C.

7. The process of producing phthalic anhydride which comprises subecting a mixture of air and crude naphthalene vapors containing analkyl-naphthalene to the action of vanadic oxide at a temperaturebetween 300 and 600 C. L

8. The process of producing phthalic anhydridc which comprisessubjecting a mix ture of crude naphthalene vapors and air under anabsolute pressure of from 2 to 4 atmospheres to the action of vanadicoxide at a temperature between 300 and 650 C.

0. The process of producing .phthalic anhydride which comprises bringinga gaseous mixture containing oxygen and vapors of crude naphthalenecontaining an alkylnaphthalene under an absolute pressure of from 2 to 4atmospheres into contact with an oxidation catalyst at a temperature offrom about 300 to 650 C.

10. The process of producing phthalic anhydride which comprises bringinga gaseous mixture containing oxygen and vapors of crude naphthalenecontaining an alkylnaphthalene under an absolute pressure of from 2 to 4atmospheres into contactwith an oxide of vanadium or molybdenum at atemperature of from about 300 to 650 C.

In testimony whereof I aflix my signature.

HARRY D. GIBBS.

Certificate of Correction. It is hereby certified that in Letters PatentNo. 159L619, granted July 6, 1026,

upon the application of Ha r D. Gibbs of Penns rove, New Jersey, for animprovement in Processes of- Taking Phthalic- Anhydride, an errorappears in the printed specification requiring correction as follows: Pa80 and insert instead guz'nones and some other compo 1', strike outresent line crystal; and t at the said Letters Patent should be readwith this'correction therein that the same may conform to the record ofthe ease in the Patent Office.

Signed and sealed this 24th day of August, A. D. 1926.

. M. J .-MOORE, Acting Commissioner of Patents.

Certificate of Correction.

It is hereby certified that in Letters Patent No. 1 591,619, grantedJuly 6, 1926, upon the application of Har D. Gibbs of Penns Grove, NewJersey, for an improvement in Processes of aking Phthalic Anhydride, anerror appears in the printed specification requiring correction asfollows: Pa 1, strike out resent line 80 and insert instead guinom's andsome other cmnpownd s m'ystal; and t at the said Letters Patent shouldbe read with this correction therein that the same may conform to therecord of the case in the Patent Office.

Signed and sealed this 24th day of August, A. D. 1926.

[m] V M. J .-MOORE,

Acting C'ommissiomr of Patems.

